In socially monogamous songbirds, many have argued that one of the primary functions of song is mate attraction (Searcy & Yasukawa, 1996), yet this hypothesis is supported by little direct evidence. The purpose of this proposed project is to examine the effects of altering male courtship vocalizations (song) and other vocalizations on female mate choice and the formation and maintenance of long-term monogamous relationships in an avian model. Specific aims are to temporarily disrupt male song and vocalizations using two reversible techniques, with different effects on vocal output, and subsequently assess the effects on female choice preferences, on initial pair formation and on the strength of the male-female relationship (pair bond). Measurements will include hormonal responses of the female to altered song and behaviors indicating attempted and successful pair bonding. It is hypothesized that these vocal disruption techniques will substantially alter male success in both pair bond formation, and, perhaps to a lesser extent, pair bond maintenance, and significantly affect female mate choice. Altering the vocal output in different ways will isolate some of the specific vocal features to which females respond, and will be used as a starting point for developing synthetic song exemplars that will further test specific female song preferences. These findings will contribute to an understanding of the importance of vocal communication in the formation and maintenance of social relationships in animals.